JENNIFER L. RAYMOND - Primate Testing - 2006

Abstract: DESCRIPTION (provided by applicant):
The vestibulo-ocular reflex (VOR) reduces motion of visual images on the
retina by evoking eye movements in the opposite direction to head
movements. A form of motor learning, known as VOR adaptation, calibrates
the VOR by gradually correcting the reflex when image motion is
persistently associated with head turns.

VOR adaptation is essential for ensuring adequate visual acuity
during head turns and for restoring proper motor and perceptual
orientation in space in response to changes in the organism or its
environment, such as occur with growth and development, aging, injury to
the peripheral or central nervous system or the donning of a new pair of
spectacles.

The proposed experiments examine the neural mechanisms of VOR
adaptation through a systematic analysis of the correlation between 1)
the patterns of neural activity present in the circuit for the VOR
during the induction of learning, 2) the altered activity in the circuit
during the expression of learning, and 3) the behavioral changes that
are induced.

The VOR is one of many motor systems that are thought to rely on
cerebellum-dependent learning to maintain normal sensorimotor function
and for recovery of function following injury. The anatomy and
physiology of the cerebellum is very regular across the extent of this
structure, therefore, the principles uncovered in studies of VOR
adaptation may be useful for the development of rational therapeutic
approaches for many forms of sensorimotor dysfunction.

The subjects in this experiment were one female and three male rhesus
monkeys (Macaca mulatta; 6-15 kg). Monkey L seemed to have impaired
vision in one eye. The eye movements reported for that monkey were
recorded in the eye with apparently normal vision.

Using sterile procedures described previously (Lisberger et al. 1994
; Raymond and Lisberger 1996 ), animals were implanted with an eye coil
for measuring vertical and horizontal eye movements and a head holder
for restraining the head.

During experiments, animals were seated in a primate chair to which
their head holder was secured. Head movement stimuli were delivered
using a servo-controlled turntable (Carco) that rotated the animal, the
primate chair, and a set of magnetic field coils (CNC Engineering)
together about a vertical axis.

All surgical and behavioral procedures conformed to guidelines
established by the U.S. Department of Health and Human Services
(National Institutes of Health) Guide for the Care and Use of
Laboratory Animals (1996) as approved by Stanford University.

VOR Gain Training
Animals were fitted with either 2.2x magnifying or 0.25x miniaturizing
goggles, which they wore in their home cages for up to 4 wk. The first
experiments were conducted after the monkey had been wearing the goggles
for at least 24 h.

Following each day's experiment (which lasted <2 h), animals were
returned to the home cage with the goggles on until the next experiment.
Experiments were most often separated by 24 h and were never separated
by <18 h.

After the animals had worn goggles for a period of several weeks, the
goggles were removed and the animals were allowed at least 1 wk to
recover in their home cages before more experiments were conducted.
After removal of the goggles, the VOR gain returned to normal in 3 d.

Testing Procedures
During an experiment, the animal was seated in a primate chair and its
head was restrained using the implanted head holder. The chair was
secured to the turntable.

Once the animal's head was fixed, the goggles were removed and the
eye coil was calibrated by having the monkey fixate a small visual
target at a number of locations. Within 10 min of the goggles being
removed, the lights were turned off.

At no time during the setup were the animals allowed to experience
combined visual and vestibular stimulation when they were not wearing
goggles. All experiments were conducted in a room specially designed to
keep all light out, and this was checked periodically by the
experimenters by adapting to the darkness in the room for 15 min and
searching for stray light.

To further control for possible light leaks into the room, some
experiments on Monkey B were conducted while the goggles remained on
throughout the hour of head movements in the dark.

Please email: JENNIFER L. RAYMOND,
[email protected]
to protest the inhumane use of animals in this
experiment. We would also love to know about your efforts with this
cause: [email protected]

Rats, mice, birds, amphibians and other animals have
been excluded from coverage by the Animal Welfare Act. Therefore research
facility reports do not include these animals. As a result of this
situation, a blank report, or one with few animals listed, does not mean
that a facility has not performed experiments on non-reportable animals. A
blank form does mean that the facility in question has not used covered
animals (primates, dogs, cats, rabbits, guinea pigs, hamsters, pigs,
sheep, goats, etc.). Rats and mice alone are believed to comprise over 90%
of the animals used in experimentation. Therefore the majority of animals
used at research facilities are not even counted.